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UPV Theses and Dissertations

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    Evaluation of commercial shrimp larval diet as replacement of live foods in mudcrab larval rearing
    Burlas, Michael Rey J. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2014-04)
    ABSTRACT The use of live food such as rotifer and Artemia entails high cost of production in the hatchery. Hence, the general objective of the study was to reduce the use of natural food in the larval rearing of mud crab. The first study was conducted to screen four types of commercial shrimp formulated larval diet (Lansy, P. japonicus, P. monodon and BP Nippai) in mudcrab Scylla serrata larval rearing. Formulated diets were fed to each stage from zoea 1 to megalopa at an equivalent of 100% dry weight of the live food. Growth index and survival were determined at the end of the experiment. Results showed that of zoea 1 fed any of the formulated diet did not molt to zoea 2. When formulated diets were fed to zoea 2, 3 and 4, there was a decreasing trend in the growth index and survival as the larvae developed. Zoea 5 fed any of the formulated diet failed to molt to megalopa stage. Among the four formulated diets, BP fed larvae had better growth and survival. BP was then used in the second study to determine the amount of formulated diet (FD) that could replace natural food (NF) such as rotifer and Artemia. Results showed that larvae fed 25% FD + 75% NF and 50% FD + 50% NF had better survival and growth than those larvae fed 100% FD + 0% NF, 75% FD + 25% NF and 0% FD + 100% NF. This study indicates that shrimp larval diet in combination with formulated diet can be used to improve the growth and survival of S. serrata larvae.
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    Comparison of the catching efficiency of the traditional and modified fish corral in Panguil Bay
    Acuña, Rodrigo E. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 1997-12)
    This study was conducted in two fishing sites of fish corral in Panguil Bay namely; Malaubang, Ozamiz City and Maquilao, Tangub City from November 21,1994 to July 10,1995. Two types of fish corral such as traditional and modified were identified. Results showed that average catch per trip was higher in the traditional fish corral (5.1 kg/day) compared to the modified fish corral (4.2 kg/day). The traditional fish corral also have a higher species richness (mean=105 species) against the modified (mean=50 species). About 90% of the catch of the traditional fish corral are commer­cially important species is significantly higher than the other type (50%). Catches of the traditional and modified fish corral largely consist of shrimps (Metapenaeus ensis: MFC; Penaeus indicus: TFC). Based on the relative density and weight of the total catch, Metapenaeus ensis (mean=222 individuals) is recorded as the most dominant species caught by the modified fish corral while Penaeus indicus (mean=38 individuals) exhibited as a dominant species in the traditional fish corral. Results of the statistical analyses on the data collected on irregular sampling dates show no significant difference on the catches between the traditional and modified. Significant difference is observed on the catches collected during the same sampling dates. Traditional fish corral is more efficient because it has higher catch per trip, species richness and high percentage of commercially important species. Modified fish cor­ral as well, is effective with regards to its catch quantity, however it is inefficient in terms of its catch quality, i.e., of low commercial value.
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    Semiparametric and parametric modelling of vibro species abundance production system
    Dequito, Angel Queenee D. (College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2017-09)
    Vibrio species that cause white spot disease and vibriosis are known to be influenced by environmental factors. In this study, the changes in the abundance of presumptive Vibrio species from a biofloc shrimp production system with respect to physicochemical and biological parameters were evaluated. Parametric and nonparametric modelling techniques were used to identify and predict changes in Vibrio abundance in relation to alkalinity, ammonia, dissolved oxygen, nitrite, pH, salinity, temperature, transparency, and phytoplankton and zooplankton densities. Abundance was found to be highly correlated with alkalinity, pH, and phytoplankton density as revealed by both parametric and semiparametric models. Generalized additive model (GAM, a semiparametric model) is the best model based on Aikaike’s Information Criterion (AIC) values in which 41.2% of the variability in the dependent variable can be explained by the predictors compared to ordinary linear regression and negative binomial models (parametric models) with 16.04% and 14.5% respectively. Prediction on the abundance can help prevent bacterial diseases in shrimp as this will provide an insight to the farmer about when to and which water parameters or predictors can be controlled. Thus, it is important to consider the use of semiparametric modelling approach as a tool for fish health management and to prevent losses in aquaculture.